Light-Emitting Diode Assembly Housing Comprising Poly(Cyclohexanedimethanol Terephthalate) Compositions

ABSTRACT

Light-emitting diode assembly housing comprising high temperature poly(1,4-cyclohexanedimethanol terephthalate) compositions containing titanium dioxide.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalApplication No. 60/716,877, filed Sep. 14, 2005.

FIELD OF THE INVENTION

The present invention relates to light emitting diode assemblycomponents comprising poly(1,4-cyclohexanedimethanol terephthalate)(PCT) compositions containing titanium dioxide.

BACKGROUND OF THE INVENTION

Light-emitting semiconductor diodes (LED's) are increasingly being usedas light sources in numerous applications due to their many advantagesover traditional light sources. LED's generally consume significantlyless power than incandescent and other light sources, require a lowvoltage to operate, are resistant to mechanical shock, require lowmaintenance, and generate minimal heat when operating. As a result, theyare displacing incandescent and other light sources in many uses andhave found applications in such disparate areas as traffic signals,large area displays (including video displays), interior and exteriorlighting, cellular telephone displays, automotive displays, andflashlights.

LED's are typically used in such applications as components inassemblies. LED assemblies comprise a housing partially surrounding atleast one LED and an electrical connection between the diode and anelectrical circuit. The assembly may further comprise a lens that isadhered to the housing and that fully or partially covers the LED andserves to focus the light emitted by the LED.

It would be desirable to make LED housings from polymeric materials, assuch materials may be injection molded and offer considerable designflexibility. However, useful polymeric compositions would preferablysatisfy a number of conditions. Since many LED assemblies are attachedto circuits boards using reflow oven welding processes that operate atelevated temperatures, useful compositions would be sufficiently heatresistant to withstand the welding conditions and minimal surfaceblistering of the housing during the welding process. Usefulcompositions would further preferably exhibit goodwhiteness/reflectivity to maximize the amount of light reflected by thehousing, have good ultraviolet light resistance, good long-termresistance to the operating temperatures of the LED assembly, and havegood adhesion to any lens material used. Thepoly(1,4-cyclohexanedimethanol terephthalate) compositions used in thepresent invention satisfy the foregoing requirements.

WO 03/085029 discloses a polyamide resin composition useful in theproduction of light-emitting diode reflectors. However, polyamides oftendo not have good color retention upon exposure to ultraviolet light orheat.

SUMMARY OF THE INVENTION

There is disclosed herein a light-emitting diode assembly housingcomprising a poly(1,4-cyclohexanedimethanol terephthalate) composition,comprising:

-   -   (a) about 40 to about 95 weight percent        poly(1,4-cyclohexanedimethanol terephthalate); and    -   (b) about 5 to about 80 weight percent of titanium dioxide;    -   (c) 0 to about 40 weight percent of at least one inorganic        reinforcing agent or filler; and    -   (d) 0 to about 3 weight percent of at least one oxidative        stabilizer,

wherein the weight percentages are based on the total weight of thecomposition.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, by the terms “light-emitting diode assembly” or “LEDassembly” is meant a device comprising at least one light-emittingsemiconductor diode, an electrical connection capable of connecting thediode to an electrical circuit, and a housing partially surrounding thediode. The LED assembly may optionally have a lens that fully orpartially covers the LED.

The LED assembly housing comprises a poly(1,4-cyclohexanedimethanolterephthalate) (PCT) composition comprising titanium dioxide.

By “poly(1,4-cyclohexanedimethanol terephthalate)” (PCT) is meant apolyester formed from a dial and a dicarboxylic acid. At least about 80mole percent, more preferably at least about 90 mole percent, andespecially preferably all of the dial repeat units are derived from1,4-cyclohexanedimethanol and are of formula (I).

At least about 80 mole percent, more preferably at least about 90 molepercent, and especially preferably all of the dicarboxylic acid repeatunits are derived from terephthalic acid and are of formula (II).

The PCT may also contain up to 10 mole percent (based on the totalamount of (I) and (II) present) of one or more repeat unit derived fromhydroxycarboxylic acids, although it is preferred that no such repeatunit be present. One particular preferred PCT contains (I) as the diolrepeat unit, (II) is 95 mole percent of dicarboxylic acid repeat unitand the other 5 mole percent of the dicarboxylic repeat unit is derivedfrom isophthalic acid, and no repeat units derived fromhydroxycarboxylic acid are present. The PCT is present in from about 40to about 95 weight percent of the composition, or preferably about 50 toabout 85 weight percent, based on the total weight of the composition.

The compositions may optionally contain up to about 70 weight percent,or more preferably about 1 to about 40 weight percent of otherthermoplastic polymers, such as other thermoplastic polyesters (such aspoly(ethylene terephthalate), poly(propylene terephthalate),poly(butylene terephthalate), poly(naphthalene terephthalate), and thelike), liquid crystalline polyesters, and the like, wherein the weightpercentages are based on the total weight of PCT and other thermoplasticpolymer.

The titanium dioxide used in the compositions may be any sort, but ispreferably in the rutile form. The titanium dioxide comprises about 5 toabout 60 weight percent, or preferably about 15 to about 50 weightpercent, or more preferably about 20 to about 40 weight percent of thetotal composition.

The surface of the titanium dioxide particles will preferably be coated.The titanium dioxide will preferably be first coated with an inorganiccoating and then an organic coating that is applied over the inorganiccoating. The titanium dioxide particles may be coated using any methodknown in the art. Preferred inorganic coatings include metal oxides.Organic coatings may include one or more of carboxylic acids, polyols,alkanolamines, and/or silicon compounds.

Examples of carboxylic acids suitable for use as an organic coatinginclude adipic acid, terephthalic acid, lauric acid, myristic acid,palmitic acid, stearic acid, polyhydroxystearic acid, oleic acid,salicylic acid, malic acid, and maleic acid. As used herein, the term“carboxylic acid” includes the esters and salts of the carboxylic acids.

Examples of silicon compounds suitable for an organic coating include,but are not limited to, silicates, organic silanes, and organicsiloxanes, including organoalkoxysilanes, aminosilanes, epoxysilanes,mercaptosilanes, and polyhydroxysiloxanes Suitable silanes can have theformula R_(x)Si(R′)_(4-x) wherein R is a nonhydrolyzable aliphatic,cycloaliphatic, or aromatic group having from 1 to about 20 carbonatoms, and R′ is one or more hydrolyzable groups such as an alkoxy,halogen, acetoxy, or hydroxy group, and X is 1, 2, or 3.

Useful suitable slimes suitable for an organic coating include one ormore of hexyltrimethoxysilane, octyltriethoxysilane,nonyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane,tridecyltriethoxysilane, tetradecyltriethoxysilane,pentadecyltriethoxysilane, hexadecyltriethoxysliane,heptadecyltriethoxysilane, octadecyltriethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-glycidoxypropyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilaneand combinations of two or more thereof. In other useful silanes, R hasbetween 8 and 18 carbon atoms and R′ is one or more of chloro, methoxy,ethoxy, or hydroxy groups.

When present, the organic coating preferably comprises about 0.1 toabout 10 weight percent, or more preferably about 0.5 to about 7 weightpercent, or yet more preferably about 0.5 to about 5 weight percent-ofthe coated titanium dioxide.

Examples of suitable inorganic coatings include metal oxides and hydrousoxides, including oxides and hydrous oxides of silicon, aluminum,zirconium, phosphorous, zinc, rare earth elements, and the like. Apreferred metal oxide is alumina.

The inorganic coating preferably comprises about 0.25 to about 50 weightpercent, or more preferably about 1.0 to about 25 weight percent, or yetmore preferably about 2 to about 20 weight percent of the coatedtitanium dioxide.

The compositions may optionally contain up to about 40 weight percent ofone or more inorganic reinforcing agents and/or fillers. Example ofsuitable reinforcing agents include glass fibers and minerals,particularly fibrous minerals such as wollastonite. Examples of fillersinclude calcium carbonate, talc, mica, and kaolin. When present, thereinforcing agent and/or filler is preferably present in about 1 toabout 40 weight percent, or more preferably about 1 to about 20 weightpercent of the total composition.

The compositions may optionally contain up to about 15 weight percent ofone or more polymeric tougheners. The toughener will typically be anelastomer having a relatively low melting point, generally <200° C.,preferably <150° C. and that has attached to it functional groups thatcan react with the PCT (and optionally other polymers present). SincePCT usually have carboxyl and hydroxyl groups present, these functionalgroups usually can react with carboxyl and/or hydroxyl groups. Examplesof such functional groups include epoxy, carboxylic anhydride, hydroxyl(alcohol), carboxyl, and isocyanate. Preferred functional groups eraepoxy, and carboxylic anhydride, and epoxy is especially preferred. Suchfunctional groups are usually “attached” to the polymeric tougheners bygrafting small molecules onto an already existing polymer or bycopolymerizing a monomer containing the desired functional group whenthe polymeric tougheners molecules are made by copolymerization. As anexample of grafting, maleic anhydride may be grafted onto a hydrocarbonrubber using free radical grafting techniques. The resulting graftedpolymer has carboxylic anhydride and/or carboxyl groups attached to it.An example of a polymeric tougheners wherein the functional groups arecopolymerized into the polymer is a copolymer of ethylene and a(meth)acrylate monomer containing the appropriate functional group. By(meth)acrylate herein is meant the compound may be either an acrylate, amethacrylate, or a mixture of the two. Useful (meth)acrylate functionalcompounds include (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate,glycidyl (meth)acrylate, and 2-isocyanatoethyl (meth)acrylate. Inaddition to ethylene and a functional (meth)acrylate monomer, othermonomers may be copolymerized into such a polymer, such as vinylacetate, unfunctionalized (meth)acrylate esters such as ethyl(meth)acrylate, n-butyl (meth)acrylate, and cyclohexyl (meth)acrylate.Preferred toughening agents include those listed in U.S. Pat. No.4,753,980, which is hereby included by reference. Especially preferredtougheners are copolymers of ethylene, ethyl acrylate or n-butylacrylate, and glycidyl methacrylate, such as EBAGMA and ethylene/methylacrylate copolymers.

It is preferred that the polymeric toughener contain about 0.5 to about20 weight percent of repeat units derived from monomers containingfunctional groups, preferably about 1.0 to about 15 weight percent, morepreferably about 7 to about 13 weight percent of repeat units derivedfrom monomers containing functional groups. There may be more than onetype of repeat unit derived from functionalized monomer present in thepolymeric toughener. It has been found that toughness of the compositionis increased by increasing the amount of polymeric toughener and/or theamount of functional groups. However, these amounts should preferablynot be increased to the point that the composition may crosslink,especially before the final part shape is attained.

The polymeric toughener may also be thermoplastic acrylic polymers thatare not copolymers of ethylene. The thermoplastic acrylic polymers aremade by polymerizing acrylic acid, acrylate esters (such as methylacrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate,n-hexyl acrylate, and n-octyl acrylate), methacrylic acid, andmethacrylate esters (such as methyl methacrylate, n-propyl methacrylate,isopropyl methacrylate, n-butyl methacrylate (BA), isobutylmethacrylate, n-amyl methacrylate, n-octyl methacrylate, glycidylmethacrylate (GMA) and the like). Copolymers derived from two or more ofthe forgoing types of monomers may also be used, as well as copolymersmade by polymerizing one or more of the forgoing types of monomers withstyrene, acrylonitrile, butadiene, isoprene, and the like. Part or allof the components in these copolymers should preferably have a glasstransition temperature of not higher than 0° C. Preferred monomers forthe preparation of a thermoplastic acrylic polymer toughening agent aremethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, n-hexyl acrylate, and n-octyl acrylate.

It is preferred that a thermoplastic acrylic polymer toughening agenthave a core-shell structure. The core-shell structure is one in whichthe core portion preferably has a glass transition temperature of 0° C.or less, while the shell portion is preferably has a glass transitiontemperature higher than that of the core portion. The core portion maybe grafted with silicone. The shell section may be grafted with a lowsurface energy substrate such as silicone, fluorine, and the like. Anacrylic polymer with a core-shell structure that has low surface energysubstrates grafted to the surface will aggregate with itself during orafter mixing with the thermoplastic polyester and other components ofthe composition of the invention and can be easily uniformly dispersedin the composition.

When present, the tougheners preferably comprise about 0.5 to about 15weight percent, or more preferably about 1 to about 10 weight percent,or yet more preferably about 1 to about 5 weight percent, of the totalweight of the composition.

The compositions may optionally contain up to about 3 weight percent ofone or more oxidative stabilizers. Examples of suitable oxidativestabilizers include phosphite and hypophosphite stabilizers, hinderedphenol stabilizers, hindered amine stabilizers, and thioesters. Whenpresent, the oxidative stabilizers comprise about 0.1 to about 3 weightpercent, or preferably about 0.1 to about 1 weight percent, or morepreferably about 0.1 to about 0.6 weight percent, of the total weight ofthe composition.

The compositions may optionally further contain up to about 3 weightpercent of ultraviolet light stabilizers or UV blockers. Examplesinclude triazoles and triazines. When present, the ultraviolet lightstabilizers comprise about 0.1 to about 3 weight percent, or preferablyabout 0.1 to about 1 weight percent, or more preferably about 0.1 toabout 0.6 weight percent, of the total weight of the composition.

The compositions are melt-mixed blends, wherein all of the polymericcomponents are well-dispersed within each other and all of thenon-polymeric ingredients are well-dispersed in and bound by the polymermatrix, such that the blend forms a unified whole. Any melt-mixingmethod may be used to combine the polymeric components and non-polymericingredients of the present invention. For example, the polymericcomponents and non-polymeric ingredients may be added to a melt mixer,such as, for example, a single or twin-screw extruder; a blender; akneader; or a Banbury mixer, either all at once through a single stepaddition, or in a stepwise fashion, and then melt-mixed. When adding thepolymeric components and non-polymeric ingredients in a stepwisefashion, part of the polymeric components and/or non-polymericingredients are first added and melt-mixed with the remaining polymericcomponents and non-polymeric ingredients being subsequently added andfurther melt-mixed until a well-mixed composition is obtained.

The LED assembly housing of the present invention may be in the form ofa single piece or may be formed by assembling two or more subparts. Whenit is in the form of a single piece, it is prepared from the PCTcomposition. When it is formed from two or more subparts, at least oneof the parts is prepared from the PCT composition. When it is formedfrom two or more subparts, one or more of those parts may be metal,ceramic, or a polymeric material other than the PCT composition. Thesubparts may be connected mechanically, by gluing, or by overmolding apolymeric material over a metal or other polymeric part. The housing orhousing subpart prepared from the composition used in the presentinvention may be formed from the PCT composition by any suitablemelt-processing method known to those skilled in the art, such asinjection molding or the like. The housing may be overmolded over ametal (such as copper or silver-coated copper) lead frame that can beused to make an electrical connection to an LED inserted into thehousing.

The housing preferably has a cavity in the portion of the housing thatsurrounds the LED, which serves to reflect the LED fight in the outwarddirection and towards a lens, if one is present. The cavity may be in acylindrical, conical, parabolic or other curved form, and preferably hasa smooth surface. Alternatively, the walls of the cavity may be parallelor substantially parallel to the diode. A lens may be formed over thediode cavity and may comprise an epoxy or silicone material.

The housings of the present invention may be incorporated into LEDassemblies used in applications such as traffic signals, large areadisplays (including video displays), video screens, interior andexterior lighting, cellular telephone display backlights, automotivedisplays, vehicle brake fights, vehicle head lamps, laptop computerdisplay backlights, pedestrian floor illumination, and flashlights.

EXAMPLES

The compositions of Examples 1-5 and Comparative Example 1 were preparedby melt blending the ingredients shown in Table 1 in a 55 mm kneaderoperating at about 300° C. using a screw speed of about 350 rpm and amelt temperature of about 330° C. Upon exiting the extruder, thecompositions were cooled and pelletized.

The following ingredients are shown In Table 1:PCT is poly(1,4-cyclohexanedimethanol terephthalate).Polyamide is a copolyamide made from terephthalic acid, adipic acid, andhexamethylenediamine with a melting point of ca. 315° C.Toughener A is EMAC® SP2260, an ethylene-methyl acrylate copolymersupplied by Eastman Chemical Co., Kingsport, Tenn.Toughener B is an ethylene/n-butyl acrylate/glycidyl methacrylateterpolymer.Lubricant is Licowax® PED521, supplied by Clariant Corp., Charlotte,N.C.Stabilizer A is an epoxy cresol novolac resin.Stabilizer B is Irgafos® 12, supplied by Ciba, Basel,Antioxidant A is Irganox® 1010, supplied by Ciba, Basel.Antioxidant B is Ultranox® 626A, supplied by G.E. Specialty Chemicals,Parkersburg, W.Va.Antioxidant C is Irganox® 1098, supplied by Ciba, Basel,Poly(butylene terephthalate) is Crastin® 6136, supplied by E.I. du Pontde Nemours & Co., Wilmington, Del.Titanium Dioxide A is RCL4 TiO2, supplied by Millenium InorganicChemicals, Hunt Valley, Md.Titanium Dioxide B is P-150, supplied by E.I. du Pont de Nemours & Co.,Wilmington, Del.Zenite® 6000 is a liquid crystalline polyester supplied by E.I. du Pontde Nemours & Co., Wilmington, Del.Wollastonite is Nayd M200, supplied by Nyco Minerals, Willsboro, N.Y.

The compositions were molded into ISO tensile bars according to ISOmethod 527-1/2 using a mold temperature of about 100° C. and tensilemodulus was determined using the same method. Notched Chary impactstrengths were determined following ISO 179/1eA. The results are shownin Table 1.

The whiteness index was determined for each composition using acolorimeter following ISO 11475:2004 and using the CIE D65 daylightilluminant at 10 degrees. Measurements were done on tensile bars thathad been heat aged in air for 2 hours at 150° C., 180° C., 200° C., or230° C. The results are shown in Table 1. Higher numbers indicate betterwhiteness.

Blistering resistance was determined using a dip soldering test. Barshaving a thickness of 0.8 mm were molded according to according to ULTest No. UL-94; 20 mm Vertical Burning Test from the compositions ofExamples 1, 2, 4, and 5 were dipped in molten solder to a depth of 15 mmin a Rhesca Co. Ltd. Solder Checker SAT-5100 for 5 or 10 seconds. Thebars were used dry-as-molded (DAM) or after conditioning for 168 hoursat 85° C. and 85 percent relative humidity (RH). The solder was at atemperature of 255, 260 or 265° C. Upon being removed from the solder,the bars were inspected for surface blisters. The results are given inTable 2.

The ultraviolet (UV) light stability of the color of the compositionswas determined by exposing ISO tensile bars to UV radiation. The sampleswere placed into the test chamber of a tabletop SUNTEST sunlightexposure system supplied by ATLAS Electric Devices Co. wherein they aredirectly exposed to UV radiation. In one set of samples, the bars wereirradiated for 300 h with a filter that cut off radiation having awavelength of less than 300 nm. The surface temperature of the samplewas 40° C. and the distance from the lamp to the sample was 22 cm. In asecond set of samples, the bars were irradiated for 46 h without afilter. The surface temperature of the sample was 75° C. and thedistance from the lamp to the sample was 4 cm. The second set ofconditions was more severe.

After irradiation, the percent reflectance of incident radiation at 630,520, or 460 nm was measured using a DATACOLOR color/meter. Thecolorimeter is calibrated by measuring a black trap and a white tiledefined as standards. The results are given in Table 3. Higherpercentages indicate better UV stability.

TABLE 1 Example Example Example Example Example Comparative 1 2 3 4 5Ex. 1 PCT 55.58 55.51 55.58 50.58 50.58 — Poiyamide — — — — — 59.6Toughener A — 3 — — — — Toughener B 2.9 — 2.9 2.9 2.9 — Talc 2 2 2 2 2 —Lubricant 0.5 0.5 0.5 0.5 0.5 — Stabilizer A 0.5 0.5 0.5 0.5 0.5 —Stabilizer B — — — — — 0.2 Antioxidant A 0.19 0.19 0.19 0.19 0.19 —Antioxidant B 0.3 0.3 0.3 0.3 0.3 — Antioxidant C — — — — — 0.2Poly(butylene terephthalate) 3 3 3 3 3 — Titanium dioxide A 30 30 — 3530 20 Titanium dioxide B — — 30 — — — Zenite ® 6000 5 5 5 — — —Wollastonite — — — — 10 20 Tensile modulus (GPa) 2.4 2.7 2.3 2.4 2.7 5.8Notched Charpy 2.5 3.6 2.1 3.1 2.8 1.9 impact strength (kJ/m²) Whitenessindex Aged at 150° C. for 2 h 62 67 47 67 65 60 Aged at 180° C. for 2 h52 61 34 55 54 39 Aged at 200° C. for 2 h 44 48 23 46 55 −8 Aged at 230°C. for 2 h 32 37 8 33 33 −40 Ingredient quantities are given in weightpercent based on the total weight of the composition.

TABLE 2 Solder temp Time Example Example Example Example (° C.)Conditioning (sec) 1 2 4 5 260 DAM 5 O O O O 85° C./85% X O O O RH/168 hDAM 10 O O O O 85° C./85% XX O O O RH/168 h [“O” denotes that noblisters were observed; “X” denotes that blisters having a diameter ofless than about 5 mm were observed; and “XX” denotes that blistershaving a diameter of greater than about 5 mm were observed.]

TABLE 3 Percent Reflectance Example Example Example Example ExampleComparative 1 2 3 4 5 Ex. 1 Irradiated for 630 nm 92 92 90 92 90 89 300h with a filter that cut off 520 nm 88 89 85 89 87 87 radiation < 300nm. Surface temperature 460 nm 82 84 79 86 84 85 of sample = 40° C.Distance from lamp to sample = 22 cm Irradiated for 48 h 630 nm 84 91 8990 87 86 without a UV filter. 520 nm 79 87 82 86 82 79 Surfacetemperature 460 nm 72 82 74 82 76 70 of sample = 75° C. Distance fromlamp to sample = 4 cm

The compositions of Examples 1-5 and Comparative Example 1 are moldedinto light emitting diode assembly housings that contain epoxy lenses.The housings made from the compositions of Examples 1-5 have goodresistance to surface blistering when the housing are welded to circuitboards, good adhesion to the epoxy lens. Furthermore, the housings madefrom the compositions of Examples 1-5 have significantly improved colorstability upon exposure to heat than the housings made from thecompositions of Comparative Example 1.

1.-17. (canceled)
 18. A composition comprising: (a) about 40 to about 95weight percent poly(1,4-cyclohexanedimethanol terephthalate); and (b)about 15 to about 50 weight percent of rutile titanium dioxide; (c) 0 toabout 40 weight percent of one or more inorganic reinforcing agentsand/or one or more inorganic fillers; (d) 0 to about 3 weight percent ofone or more oxidative stabilizers; and (e) an ethylene/(meth)acrylatecopolymer and/or an ethylene, ethyl acrylate or n-butyl acrylate andglycidyl methacrylate terpolymer; wherein the weight percentages arebased on the total weight of the composition.
 19. The composition asdefined in claim 18, wherein the composition contains from about 1% toabout 20% by weight of an inorganic filler.
 20. The composition asdefined in claim 18, wherein the composition contains from about 1% toabout 20% by weight of the inorganic reinforcing agent, the inorganicreinforcing agent comprising glass fibers.
 21. The composition asdefined in claim 18, wherein the composition contains from about 0.1% toabout 3% by weight of the oxidative stabilizer.
 22. The composition asdefined in claim 20, wherein the composition contains from about 0.1% toabout 3% by weight of the oxidative stabilizer.
 23. The composition asdefined in claim 18, wherein the composition further comprises fromabout 0.1% to about 3% by weight of an ultraviolet light stabilizer. 24.The composition as defined in claim 18, wherein both theethylene/methacrylate copolymer and the ethylene, ethyl acrylate orn-butyl acrylate and glycidyl methacrylate terpolymer are present in thecomposition.
 25. The composition as defined in claim 18, wherein thecomposition further comprises a polymer having attached to it functionalgroups that react with the poly(1,4-cyclohexanedimethanolterephthalate).
 26. The composition as defined in claim 25, wherein thecomposition contains from about 1% to about 20% by weight of aninorganic filler.
 27. The composition as defined in claim 18, whereinthe composition further contains polybutylene terephthalate,polyethylene terephthalate or a liquid crystalline polyester.
 28. Ahousing for a light-emitting diode for reflecting light in an outwarddirection, comprising a composition as defined in claim
 18. 29. Acomposition comprising: (a) about 40 to about 95 weight percentpoly(1,4-cyclohexanedimethanol terephthalate); and (b) about 5 to about60 weight percent of titanium dioxide; and (c) from about 0.5% to about15% by weight of a polymer that has attached to it functional groupsthat react with the poly(1,4-cyclohexanedimethanol terephthalate). 30.The composition as defined in claim 29, wherein the functional groupsthat are attached to the polymer comprise epoxy groups.
 31. Thecomposition as defined in claim 29, wherein the functional groups thatare attached to the polymer comprise carboxylic anhydride groups,hydroxyl groups, carboxyl groups, or isocyanate groups.
 32. Thecomposition as defined in claim 30, wherein the epoxy groups are graftedto the polymer that reacts with the poly(1,4-cyclohexanedimethanolterephthalate).
 33. The composition as defined in claim 29, furthercomprising from about 1% to about 20% by weight of one or more inorganicreinforcing agents.
 34. The composition as defined in claim 29, furthercomprising from about 1% to about 20% by weight of one or more inorganicfillers.
 35. The composition as defined in claim 33, wherein theinorganic reinforcing agent comprises glass fibers.
 36. The compositionas defined in claim 29, further comprising from about 0.1% to about 3%by weight of an oxidative stabilizer.
 37. The composition as defined inclaim 34, wherein the inorganic filler comprises talc.
 38. Thecomposition as defined in claim 29, wherein the composition furthercontains polybutylene terephthalate, polyethylene terephthalate or aliquid crystalline polyester.
 39. The composition as defined in claim29, further comprising an ethylene/(meth)acrylate copolymer.
 40. Ahousing for a light-emitting diode for reflecting light in an outwarddirection, comprising a composition as defined in claim
 29. 41. Acomposition comprising: (a) about 40 to about 95 weight percentpoly(1,4-cyclohexanedimethanol terephthalate); and (b) about 5 to about60 weight percent of titanium dioxide; (c) about 1 to about 20 weightpercent of one or more inorganic reinforcing agents; (d) from about 0.1%to about 3% by weight of one or more oxidative stabilizers; (e) anethylene/(meth)acrylate copolymer and/or an ethylene, ethylacrylate orn-butylacrylate and glycidyl methacrylate terpolymer; and (f) a polymerhaving attached to it functional groups that react with thepoly(1,4-cyclohexanedimethanol terephthalate).
 42. The composition asdefined in claim 41, wherein the titanium dioxide is present in anamount from about 15% to about 50% by weight.
 43. The composition asdefined in claim 41, wherein the inorganic reinforcing agent comprisesglass fibers.
 44. The composition as defined in claim 41, furthercontaining polybutylene terephthalate, polyethylene terephthalate or aliquid crystalline polyester.
 45. A housing for a light-emitting diodefor reflecting light in an outward direction, comprising a compositionas defined in claim 41.